Air conditioning system



May 2, 1961 A. l. McFARLAN AIR CONDITIONING SYSTEM Filed Jan. 24, 1956 r i Q T V% ATTORNEYS Unite tates This invention relates to refrigeration and heating for air conditioning, and more in particular to an improved method of and systems for conditioning air where ground water is used as a cooling medium.

An object of this invention is to provide an improved system and mode of operation whereby a cooling load is handled in the most efficient manner at all times, and with a minimum amount of equipment. Another object is to provide for the etlicient and dependable operation of a system for maintaining comfort conditions throughout the entire year, by cooling and dehumidifying the air in warm and humid weather, by selectively cooling or dehumidifying when desirable, and by heating the air in cold weather. A further object is to provide an air conditioning system which is adaptable to varying conditions of use and which may be readily modified to allow for changed conditions after installation. A still further object is to provide a system wherein maximum advantage may be had from the use of cold water, for example, from wells, with the result that a minimum quantity of water will be used.

Air conditioning systems have been provided using a secondary heat-transfer or cooling medium such as water or brine, which is cooled by a refrigeration system and in turn is used to cool air, with the cold water or brine being pumped through coils or sprayed in the path of the air. With such systems the heat is transferred from the air to the secondary medium, and thence to the refrigerant; from the refrigerant the heat is normally transferred to water which may be re-circulated through a cooling tower and thus cooled by partial evaporation in a stream of outside air. With such systems auxiliary means has been provided for heating the air in the winter.

The present invention relates to the general type of system to which reference has been made, but the water is not recirculated during the cooling operation. In the illustrative embodiment, a minimum stream of water from a well or wells is first cooled to a predetermined temperature by a refrigeration system and the stream of water then passes to the air cooling zone which may be formed by air cooling coils positioned within or adjoining the conditioned space. The air is blown through these coils in the air cooling zone, and it is cooled and dehumidified, and the stream of water takes up a substantial amount of heat so that its temperature is raised considerably. Under some circumstances this water from the cooling coils is used for refrigerant condensing so that a single stream of the water acts as the medium to produce all of the air cooling and also to cool the refrigeration system. In accordance with another aspect of the invention, a stream of water may be used for condensing refrigerant in supplemental refrigeration systems. The water may then be wasted or returned to the ground or it may be used for roof cooling; also, it may be used as a source of warm water at a temperature, for example, of 80 F. to 90 F. for more or less general heating or for re-heating purposes in the, air conditioning system.

' atet In accordance with the present invention the quantity of refrigeration capacity required is merely that necessary to carry the cooling load and produce the dehumidification which the higher temperature water will not carry. The quantity of water which is utilized depends to some extent upon the amount which is economically available, but consistent with economy of operation, the quantity of water is kept at a minimum; this reduces the required sizes of the well and the pumps and piping, and it also reduces the amount of refrigeration capacity to a minimum value. Where supplemental refrigeration is required along with an air conditioning system, provision is made for supplying the water from the well directly to the supplemental refrigeration and a storage tank may be provided which is kept substantially full during normal use so that the supplemental refrigeration may be operated with a very substantial consumption of water for short periods of time, for example, without calling upon an auxiliary water supply. Thus, the single source of water may be used for the air conditioning system and the same source may be used for the auxiliary refrigeration condenser-cooling.

With the type of system described, the amount of refrigeration capacity is a function of the quantity of water utilized, rather than a direct function of the quantity of heat removed from the air. that with such systems an attempt to increase the capacity by merely increasing the rate of water flow normally would tend to produce a higher temperature for the water being circulated and this materially decreases the dehumidifying capacity. The present invention permits a suificiently low temperature for the water being circulated to give optimum humidity control, and the water and the apparatus are used etficiently at all times.

The air conditioning system of the present invention may be so designed as to be highly efiicient'not only during use for air cooling and dehumidifying but also during use as a heating system by merely utilizing reverse cycle heating or by also attaching a water heater to the water distribution lines. This result is possible because the relatively small quantity of water which is circulated for dehumidifying and cooling the air is of the order of the amount of water which may be circulated for heating the air; and, the coils and pipes therefore handle substantially the same amount of water the year round, and the air blowers or fans may handle the same amount of air at all times. Thus, the system is eflicient and it uses minimum water and consumes minimum power.

With systems of the above character which depend upon water from wells or from some other similar source as the circulating cooling medium, there may be a tendency toward a rise in the water temperature at the source;

for example, in some communities an increase in quantity of water removed from the ground or the return'of water to the ground by dilfusion wells may cause an appreciable rise in the temperature of the ground water. This is noticeable in a community such as the portion ofLo-ng Island near New York City. In addition to the rise in the ground water temperature there may be a falling off 7 of the normal water level so that the capacity of a Well may be reduced, or governmental authorities may reduce the amount of water which may be used. The present invention contemplates obtaining the maximum cooling eifect from a minimum amount of water used at all times, but it also is sufficiently versatile to be adaptable to proper operation even when the temperature of the: supply water rises or when the amount of supply wateris reduced.

The invention accordingly consists in the. features: of;

construction, combinations. or elements, arrangements of It should be noted will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the drawing:

Figure l is a schematic showing of one embodiment of the invention; and,

Figure 2 is a schematic representation of a modified arrangement of the embodiment of Figure 1.

Referring to the drawing, an air conditioning system is represented having a water cooling refrigeration system 2 as part thereof which comprises an electric motor driven compressor 4, a condenser-receiver 6 and an evaporator 8. The compressed refrigerant from the compressor is condensed in the condenser-receiver and the liquid refrigerant passes through a line 10 shown in broken lines and an expansion valve 12 to the evaporator 8 where it is evaporated, and the gas refrigerant returns to the compressor through a line 13 also shown in broken lines. Controls are provided for the refrigeration system which are of known construction and are not shown.

Evaporator 8 is the cooling element in a water cooling heat exchanger 14 through which a continuous stream of water flows at a constant rate after it has been pumped from a well 16 by a pump 18, and delivered through a water line 20. Heat exchanger 14 is of the shell and tube type with tubes forming the evaporator, and thus carrying the-refrigerant along a plurality of parallel evaporating paths and with shell 17 confining the water and providing a path of flow for the water in heat exchange relationship with the refrigerant. A plurality of bafiles 19 direct the water first downwardly and thence upwardly again so that it flows rapidly past the tubes a number of times. Refrigerant is carried from the expansion valve 12 to each group of the tubes 15 by a refrigerant distributor tube 11, and the gas refrigerant is collected at the right in a header 21 and passes back to the compressor through line 13. At the right hand side of each of the lower baffles 19 there is a cleanout or purge connection 23, each of which is provided with a valve which is periodically opened to discharge sediment collected in the bottom of shell 17.

Cool or chilled water from the heat exchanger '14 passes through a pipe or line 22 and a valve 27 to a distribution pipe or line 25 which is branched and distributes the cold water to a plurality of air heat-transfer coils positioned in difierent zones of the air conditioned space and, illustratively represented by three air cooling or heat-transfer units 24, 26 and 28. Each of these air heat-transfer units comprises a water coil having fins thereon past which, for example, a stream of the air to be cooled and dehumidified is drawn or blown by a fan 32 counterflow to the water. During such operation the cold Water flows through these coils 30 and the water is discharged from units 24 and 26 to a water line 34 and from unit 28 to a water line 36.

Each of the coils 30 has a bypass line 31 connected in parallel therewith by a three-way valve 33. Valve 33 is initially positioned as shown so that the entire stream of water flows through coil 30, but when the cooling demand is diminished, valve 33 is turned counter-clockwise so that part of the stream of water is diverted through line 31 to line 34 with there being a corresponding reduction in the flow through the coil 30; at the extreme position all of the water is diverted through line 31 and no water flows through coil 30.

Water line 36 is connected to line 34 by a three-way valve 38 which may be adjusted to limit the flow of water from line 36 to line 34, and also may be turned to connect line 36 to a water discharge line 42. Illustratively, water may be taken from line 42 for auxiliary cooling purposes, for example, for a cooling function at a remote point.

Line 34 has a pump 39 therein and is connected through a line 40 to the upper section 43 of the righthand header of the condenser-receiver 6. Thus, thewater aaaasas flows from line 40 first to the left through the upper section of tubes 44 to the left'hand header 45, and thence to the right through the lower section of tubes 44 to the lower right-hand or outlet header section 47. The refrigerant is in the shell 49 and is condensed by the water in the tubes, which water is thereby heated. The water flows from header section 47 through a three-way discharge valve 46 which directs the water through a line 41 to a storage tank 48. Tank 48 has an overflow and discharge line 59 which limits the water level in the tank, and when the water level rises above the top of this pipe the xcess water is discharged to waste or re turned to the ground. As explained elsewhere, this water may be Used for other purposes; for example, as a source of warm or hot water or for roof cooling. In this embodiment, provision is made for storage of a large amount of the water in tank 48 from which the water is directed as required by a pump 51 through a pipe 53. In this embodiment a stream of this water is used for cooling the condensers 52 of a number of individual auxiliary refrigeration units or systems 54 which are used to cool refrigerator boxes, for example, refrigerated show cases each cooled by an evaporator 56.

Thus, when the air conditioning system is operating, the water passes from the coils 30 through the condenser and to tank 48, and water is withdrawn from the tank as desired to cool the condensers of the refrigeration units or systems 54. However, when the refrigeration units or systems 54 are to be operated when the air conditioning system is not in operation, then water is still withdrawn from the tank 48 for cooling the unit condensers. Thus, for example, if the water level in the tank falls during cool weather, the water from the well is passed from the pump directly to the tank 48. Under such circumstances, a three-way valve 58 in line 20 is turned so as to connect line 20 to a line 60 leading to the tank; and, at the same time, the operation of pump 18 is placed under the control of a control unit 62. Control unit 62 has high and low limit switches 64 and 66 adapted to start pump 18 whenever the water level in the tank drops below the level of switch 66 and to maintain the pump in operation until the water level rises above switch 64. The control unit 62 is inoperative when the air conditioning system is in actual operation. Under some conditions of operation, line 60 is omitted and valve 27 is moved to a position wherein line 22 is connected to a line 61 which extends to tank 48. Thus, the water from the well passes through the heat exchanger 14 prior to passage to tank 48 so that the silt and sand are trapped out as explained above. With this water fiow, the system may also be operated for reverse cycle heating.

There may be conditions of operation when the water level in tank 48 falls to a very low level even with pump 18 operating continuously. This contingency is provided for by a control unit 68 which controls a valve 70 and which is opened to deliver water from a city water main or line 72 to the tank. Control unit 68 is similar to control unit 62 and has high and low limit switches 74 and 76, and the unit opens the valve when the water level falls to switch 76 and closes the'valve when the water level rises to switch 74.

Water from the condensers 52 passes to line 78 which is connected to the overflow and discharge pipe 50 through a solenoid valve 81 which is adapted to restrict or stop the flow of water from line 78. Thus, the water may flow through line 50 to waste or for other purposes, or valve 81 may be partially or completely closed to divert part or all of the water to other devices utilizing heated water; for example, at F. to F. In this embodiment, water is withdrawn from line 78 by a pump 80 in a line 82 which leads to a re-heat or auxiliary coil 84 in the cooling or heat-transfer unit 28. Thus, when the air is being cooled by coil30 in unit 28 to reduce its moisture content so that theair from coil 30 is below the desired coil output temperature, then the air is reheated by coil 84 to the desired temperature. The reheat eifect is provided because unit 28 is in an inside space which requires dehumidifying with little or no cooling, and the reheating is controlled by a thermostat which controls the operation of pump 80 and the closing of valve 81. Water from coil 84 is discharged to line 50.

Line 82 is also connected to line 53 by a line 83 having a valve 85 therein so that re-heat Water may be supplied directly from tank 48 through line 82 to coil 84 by pump 51 when units 54 are not operating- Also, as will be explained below, it is desirable at times to provide some cooling effect in the space conditioned by unit 28 when the air conditioning system is not operating to cool the air. Under such circumstances the relatively cool water from the well is pumped directly to tank 48 where it is available for cooling the condensers 52 or for pumping through coil 84.

Thus, a properly designed air conditoning system is provided which is operated to supply conditioned air to the space or spaces to be conditioned in suflicient quantity and having such characteristics that the sensible and latent heat loads are handled. Thus, the proper quantity of conditioned air passes from the conditioning apparatus or zones with the desired Wet bulb and dry bulb temperature characteristics so that the internal sensible heat and internal moisture load will be picked up, thus producing and maintaining the desired wet bulb and dry bulb temperature conditions in the conditioned space. This operation may be illustrated on a psychometric chart with the following typical set of conditions as represented as follows:

(I) A represents the peak design conditions of the outside or fresh air, illustratively, at 95 F. dry bulb and 75 F. wet bulb, and it is considered that 25% of this fresh air is added to 75% of recirculated air passing to the conditioning zone.

(2) B represents the desired conditions in the conditioned space or room, illustratively, 80 F. dry bulb and 66.7 F. wet bulb, which is 50% relative humidity; and, it is assumed that this condition is desired when the above-mentioned peak design conditions for the outside air exist.

(3) C represents the conditions of the air which results from mixing 75% return or recirculated air with 25% fresh air all as specified above, and such mixed air is at 83.7 F. dry bulb and 69 F. wet bulb.

(4)' D" represents the required conditions of the cooled and dehumidified air at which that air' must leave the conditioning apparatus or zones to produce the desired conditions in the conditioned space. This required condition for the cooled air is determined from the total internal sensible heat and latent heat loads of the conditioned space.

' It is noted that at the condition B of 80 F. dry bulb and 50% relative humidity, the theoretical dew point is 60 F. However, in actual practice air leaves the typical finned coils having counterfiow water cooling at from about 80% relative humidity to about 98% relative humidity, depending upon many factors such as the ratio of sensible to latent heat, the depth of the coil, the air velocity through the coil, the temperature of the water entering the coil and the velocity of the water flowing through the coil. In the illustrative case, the air leaves the coils at 90% relative humidity and at a dry bulb temperature of 62 F. and this exactly satisfies the calculated design conditions mentioned above.

7 Under these circumstances the water temperature entering the coils must be sufi'lciently below the 62 F. dry bulb cooled air temperature to produce these desired con: ditions of the air leaving the coils. Also, regardless of how much water is used in the cooling coils, the water must be low enough in temperature to reduce the coil a 9. 2 see into the system and the flow is aided by the booster e e a d e a r leaves he. o to au e condensa i a at a rate such as to produce the desired60 F. wetbulb of condition D" for the cooled air leaving the cooling zones. In actual practice, the maximum temperature of f water entering the coils is about 55 F. in order to meet practical requirements for depth of coil.

However, if a somewhat lower water temperature is provided, particularly a temperature of about 10 F. below the dry bulb temperature of the air leaving .the coils, then the desired wet bulb and dry bulb temperature conditions for the air leaving the coils may be easily ob: tained with minimum coil size.

Since one ton of refrigeration is equal to twelve thousand B.t.u.s per hour, the rise in temperature of one gallon of water per minute to produce one ton of refrig. oration will be twelve thousand divided by eight and one-third (pounds per gallon of water) times sixty (minutes per hour) and this equals 24 F. In other words, if the difierential in temperature between the entering and leaving water in the cooling coils is 24 F., then the system will produce one ton of refrigeration for each sixty gallons of water per hour or each gallon of water per minute.

Assume that well water is available at 60 F. and that its temperature is reduced in heat exchanger 14 to 52 F.

which is a reduction of eight degrees, and that the temperature then rises in the cooling coils to 76 P. which is 24 F. rise or three times the original eight degree drop. Then the refrigeration system is producing one-third of a ton of refrigeration for each ton of cooling of the cooling coils. Stated differently, the Water is cooled eight degrees and then has its temperature raised twenty-four degrees so that each gallon of water is cooled only one third as much as it is later heated. This relatively small amount of cooling by the refrigeration system is efiective, however, to condense a very substantial amount of moisture.

In an illustrative embodiment, the water is cooled through a range of 8 F. to 12 F., and its temperature is brought down to 55 F. or lower, the specific temperature depending upon the temperature and amount of the water entering the water-cooling zone at the evaporator. With those conditions the temperature of the cooled water is reduced to substantially within the range of 48 F. to 55 F., it being understood that this condition is satisfied, even though the refrigeration capacity may be sufiicient to cool the Water a few degrees cooler under some conditions of operation. The water thus cooled is then heated through a range of 20 F. to 30 F., when passing through the air-cooling coils. This produces cooling of the air by the water in terms of heat units at least equal to twice the amount of cooling produced on the water when passing through the evaporator.

' It has been pointed out above that the present system.

is quite versatile so that it may be adapted to meet a wide variety of conditions and circumstances. Furthermore, if the temperature of the well water rises after the installation has been made, an auxiliary cooler or pre-cooler may be inserted in line 20 to cool the stream of water and compensate for the rise in well water temperature, and the heat exchanger 14. receives Water at the temperature for which it was designed so that itand the remainder of the system continue to operate with no change, andwith the original efficiency and dependability. Furthermore, the system may be operated under some circumstances without any cooling of the water, for example, on days Where there is relatively low humidity and approximately the same outside temperature as is desired in the conditioned space so that the entire load is only the internal load, namely the load produced by occupants, lights, machines, etc. During operation'with or without artificial cooling, Water from the well is pumped pump. 39. e

and fin surface temperatures sufficiently where the water In the embodiment of the invention of Figure 1, there 7 is a constant rate of flow through the system with the rate being such that each of the coils 30 is supplied with the desired quantity of cold water. As explained above, valves 33 act independently to divert part or all of their streams of water from their coils so as to reduce the cooling efiects. Under some circumstances, it is desirable to reduce the quantity of water flowing when there is a reduction in load and for this purpose valves 33 are replaced by throttling valves 133, as shown in Figure 2. Each of valves 133 acts independently to reduce the flow of water through its coil 130, and there are no bypass lines 31. Each valve 133 has a bulb 135 in the path of the air flowing from its coil 130. This arrangement reduces the water consumption, and is somewhat effective to reduce the temperature of the water below the design temperature when the load is reduced so as to increase the dehumidifying effect, and reduce the space temperature.

Under other circumstances, it may be desirable to maintain a continuous flow of chilled water through the evaporator 14, coils 30 and condenser 6 even when the cooling load decreases due to a decrease in outside ambient temperature. With this arrangement, a reduction in the load causes the water flowing from the coils to the condenser to be at a lower temperature, with the result that the condensing temperature is reduced. This reduction in condensing temperature reduces the head pressure on the compressor and effects a corresponding reduction in the suction pressure, with the result that the evaporator temperature is reduced. The reduction in evaporator temperature effects an immediate reduction in the temperature of the chilled water leaving the evaporator. This reduction in the temperature of the chilled water flowing to the coils causes the coil temperature to be reduced so that there is an increase in the dehumidification of the air. That is, a drop in the coil temperature reduces the air temperature to a lower effective dew point, and therefore the air contacting the coils is subjected to increased latent cooling. Under such circumstances, the air may be reheated as discussed above in connection with the use of the auxiliary coil 84. Furthermore, the quantity of air being cooled may be reduced by throttling the flow of air under the. control of a thermostat, for example, in the conditioned space. t

It is thus seen that a reduction of load on the system produces a reduction in the effective coil temperature so as to increase the dehumidification of the air. Hence, the system automatically compensates for the fact that the decrease in the sensible load upon an air conditioning system is often accompanied by a need for an increase in the dehumidification. That is, on summer days of extremely high humidity, the sensible load is apt to be relatively low, whereas on days when the temperature is extremely high, the latent load is apt to be low.

An important aspect of the present invention involves the use of coils 30 having such characteristics that the temperature of the air is reduced substantially the same amount that the temperature of the water is raised; and, with the counterflow relationship between the air and the water in the coils, the temperature gradient or difference between the temperatures of the air and the water is substantially uniform throughout the coil. Assume in the illustrative embodiment that the temperature of the water is raised from 52 F. to 76 F., and the temperature of the air is reduced from approximately 84 F.

the air temperature. This arrangement insures maximum coil performance in actual operation because all portions of the coil and fin assembly are used withinthe'ir range of optimum temperature gradients During operation the temperature of the air drops as it passes through the coil, and when it reaches its dew point the moisture starts to condense upon the coil and fin surfaces. During more or less normal operation the air reaches the dew point and the moisture starts to condense upon the coil and fin surfaces so that the coil and fin surfaces are wet through approximately the last third of the depth of the coil in the air stream. However, when the entering air has a relatively low moisture content, then the dew point will not be reached until the air moves substantially further along its path; whereas, when the moisture content is very high, the air may reach its dew point relatively near the zone where it enters the coil. The coil and its fins pick up heat at an increased rate through the zone where the coil and fin surfaces are wet. Thus, the feature of having a deep coil so that there may be a very substantial zone of wet surfaces insures improved operation at high humidity conditions because of the great increase in heat transfer capacity effected by the substantially increased area of wet fin and coil surfaces.

In units 24 and 26 of the illustrative embodiment, the air is drawn through the coil and then through the fan so that any drops of condensed moisture in the air stream are thrown from the stream by the fan and do not pass out in the stream. In unit 30, the air is blown through the coil, and any drops of the moisture are reevaporated by coil 84 or are removed by bafiies at the coil outlet.

As indicated above, the system as just described also may be used as a heating system in the winter and for this purpose a boiler 86 is provided which is adapted to produce steam for a heating coil 88 of a water heating unit 90 which has a shell 92. Shell 92 is connected at the top to the water distribution line 25 and at the bottom to a line 94 which terminates at valve 46. During the heating cycle valve 27 is turned counterclockwise onequarter turn so as to connect lines 22 and 61 and valve 46 is turned clockwise so as to connect the outlet water header 47 with line 94. Thus, a closed water circuit is provided which extends from the coil water discharge line 34 through pump 39, through line 40, through the water circuit of the condenser-receiver 6 to the outlet header 47, through valve 46 to line 94, through the water heating unit 90 and thence through the water distribution line 25 and through the coils 30 to the line 34. The flow in this circuit is produced by pump 39 which is operated continuously, and the refrigeration system is also operated with pump 18 directing water to the evaporator, but then from line 22 the water flows through valve 27 and lines 61 to the water storage tank 48. Thus-the water flowing to the storage tank 48 is cooled, whereas the water from line 40 flowing through the condenser is heated and delivered through line 94 to the water heating unit where it is further heated. The water passes from the water heating unit at a substantially elevated temperature so that the coils 30 now act as air heating coils. The refrigeration system is now acting as a reverse cycle heating unit receiving the relatively cool water from the coils 30 and elevating the temperature substantially; the Water heating unit 90 then acts as a booster heater to further heat the water to such a temperature as is required to maintain the desired temperature of water in coils 30. The valves 33 are thermostatically controlled during both the cooling and heating operations so that the flow of water through each coil 30 is restricted or stopped by the satisfying of the thermostat.

As indicated above, unit 28 conditions a space such as an inside room which requires dehumidifying and little or no cooling in summer; and in winter this space requires little or no heating and may then require dehumidifying or even some cooling. Under such circumstances, the valve 33 on that unit is turned to prevent flow through coil 30, and valve is opened to circulate the relatively cool water from tank 48 through coil 84 to provide cooling. The temperature of this water is sufiiciently low to insure proper humidity control, but if necessary'this'water aa ataa temperature may be reduced further by a separate cooler unit.

This system permits the selection and design of the coils 30 and the piping and pumps such that the system will work, with high efiiciency whetherit is operating to heat or to cool the conditioned spaces. This uniformly high efliciency is possible because of the low rate of water flow during the cooling operation. The illustrative emboodiment includes the use of a single stream of water for the entire system for cooling the air, and the same stream is.

used for condenser cooling for the auxiliary refrigeration units or systems and this would normally require an additional and equal stream of water. Thus, a single well and pump and a single pipingsystem does work which would otherwise be done with substantially twice the water sup ply facilities.

Under some circumstances the auxiliary heating unit 90 and its boiler 86 may be omitted and the entire heating load will then be carried by the reverse cycle operation of the refrigeration system. The invention contemplates that the refrigeration system carry the entire heating load during periods when only a small amount of heating is required and that the boiler 86 be used only when the reverse cycle heating is inadequate. Thus, for example, during the spring and fall when a small amount of heating is required in the early morning, the system is operated solely as a reverse cycle heating system. Later in the same day it may be desirable to provide for air cooling, in which case the operation is changed so that coils 30 act as air cooling coils. During periods of the year when substantially continuous heating is required the boiler may carry the basic heating load and the refrigeration system may be used only when there is an exceptionally heavy heating load. On the other hand the refrigeration system may be operated to carry the major or basic heating load and the boiler is then used to carry only the marginal load during peak load periods. In climates such as the Northern portion of the United States, with either manner of operation the size of the boiler required for heating is cut substantially because the refrigeration system will carry a substantial portion of the peak load. a

In warmer climates the heating load may be so small that little or no auxiliary heating is required. The determination of whether the refrigeration system or the boiler carries the basic heating loads depends largely upon the relative costs of operating the boiler and the refrigeration system. For example, if the cost of electric power for operating the refrigeration system is relatively high and the cost of the boiler fuel is relatively low, the boiler carries the base load and the reverse cycle heating is used only during peak loads. On the other hand when the cost of electric power is low and the cost of boiler fuel is high, the boiler is used only for peak loads.

The entire operation of the system is automatic with provision for humidity and temperature control in the summer in each space which is conditioned and with automatic temperature control in the cool weather. The shift from summer control to winter control is automatic, and many of the control elements perform control functions for the two conditions of operation. Where accurate humidity control is necessary in the space conditioned by unit 28, the valve 33 of that unit is controlled by a roomhumidistat or wet bulb controller or by a dew point thermostat in the conditioned space, or in the stream of air leaving the cooling coil 30. With such operation a dry bulb thermostat would still contol the amount of re-heating supplied by coil 84. It should be understood that the showing of-two of the units 24 and 26 is illustrative, and there may be a plurality of such units and the system may include two or more units such as 28.

Under some circumstances pump 39 is positioned directly above the heat unit 90, and in such case the well an additional pump. It should be noted that pump may also be eliminated under some circumstances, in which case pump 51 supplies sufiicient pressure in line 78 tocause the water to flow through coil 84.

The invention contemplates the omission of the heating function when that is not desired, and the basic system may be installed without the heating system, and, then the heating system may be added later. Under such circumstances pump 39 would be installed only at the time that the heating system is installed. The basic system may be installed also with minimum or no refrigeration system which may be installed later. Furthermore, as has been pointed out above, a booster cooler may be inserted in line 20 so as to effect a primary water cooling.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is tobe understood that all matter hereinabove set forth, or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

This application is a continuation-in-part of my prior application, Serial No. 238,430, filed July 25, 1951 and now abandoned, and relates back to said prior application for all common subject matter.

I claim:

1. In an air conditioning system, the combination of, a refrigeration system including an evaporator and a condenser, means to direct a primary stream of water through said evaporator thereby to cool the water, heat transfer means connected to pass the primary stream of water into heat exchange relationship with air to be conditioned, auxiliary heating means in heat exchange heat is transferred to the air through said heat transfer a means, and means including an auxiliary refrigeration system further utilizing the primary stream of water when the secondary stream is being recirculated to heat the air.

2. A system as described in claim 1 which includes, a storage tank, means to direct said primary stream of water into said tank, means to direct the water from said tank for utilization in the auxiliary refrigeration system, and means to supply water to said tank when the demand by'said auxiliary refrigeration system exceeds the supply from said primary stream of water.

3. In a system of the character described, the combination of, a primary refrigeration system including an evaporator and a condenser, means constituting a supply of a primary stream of water, means to pass air through an air conditioning zone, means to pass said primary stream of water through said evaporator and thence through said air conditioning zone and through said condenser, utilization means connected to receive the water from the primary stream after it passes through said condenser, a plurality of auxiliary refrigeratian units each having a condenser, means connecting the utilization means to the condensers of the auxiliary units to cool said condensers by water from said utilization means, air heating means in the air conditioning zone connected to receive water from the condensers of said auxiliary refrigeration units to reheat the air cooled by the primary stream of water, and means to supply water directly to said utilization means.

4. Apparatus as described in claim 3 which includes, means to divert the stream of water passing from said evaporator directly to said utilization means and means to circulate water through said condenser of the primary refrigeration system and said air conditioning zone.

5. In a system of the character described, the combination of, a primary refrigeration system including an evaporator and a condenser, means constituting a supply of a primary stream of water, means to pass air through an air conditioning zone including blower means and a heat transfer water coil, means to pass said primary stream of water through said evaporator and thence through said air conditioning zone and through said condenser, receiving means to receive the water after it passes through said condenser, means to divert the stream of water from said evaporator to said receiving means, means to trap water of the primary stream in the condenser and heat transfer coil and re-circulate water through said coil and condenser whereby the heat of condensation is delivered to air in said air conditioning zone, auxiliary heating means to provide additional heating of the air, and means connected to said receiving means comprising an auxiliary refrigeration system further utilizing the water therein.

6. A system as d'fSCl'ibEdiIl claim 5 in which the utilization means is a coil in said air conditioning zone, means to pass a stream of water from said receiving means.

through said coil in said air conditioning zone, and wherein said auxiliary heating means is a steam heating unit in heat exchange with the water recirculated through said coil and condenser, and a boiler to supply steam thereto.

7. Apparatus as described in claim 6 wherein said evaporator is of the evaporator tube type having a shell through which the water passes to be cooled, and means to discharge accumulated sediment from said shell.

8. In a system of the character described the combination ofa primary refrigeration system having an evaporator and a condenser, a heat exchange coil, an auxiliary refrigeration system having a condenser, a reheat coil, an auxiliary heater, a source of cool water, a tank, conduit means forming a path of flow from the source of water through said evaporator of the primary refrigeration system, heat exchange coil and condenser of the primary refrigeration system to the tank for cooling air contacting the heat exchange coil, conduit means cooperating with said last named means to form a closed circuit through the condenser of the, primary refrigeration system, auxiliary heater and heat exchange coil for heating air contacting the coil, a conduit from the evaporator to the tank, valve means in the conduit means for shifting from a cooling to a heating operation and diverting water from the evaporator to the tank, and conduit means forming a path from the tank through the condenser of the auxiliary refrigeration system and reheat coil whereby the water which cools the air contacting the heating exchange coil is used to reheat cooled air contacting the reheat coil.

9. In the art ofair conditioning, the steps of passing a stream of water from a well through a cooling evaporator to reduce the temperature of the water through a range of 8 F. to 12 F. to substantially within the range of 48 F. to F., passing the water thus cooled through an air conditioning zone, passing air through said zone in countercurrent heat exchange relationship with the water to cool the air, maintaining the air and water in heat exchange relationship for a sufiicient period to heat the water through a range of 20 F. to 30 F. and thereby producing a cooling of the air by the water in heat units at least equal to twice the amount of cooling produced on the Water in heat units by the evaporator.

References Cited in the file of this patent UNITED STATES PATENTS Ashley Sept. 11, 1951 

